> Ignotum per ignotius, I fear. Can you give some concrete examples?

In 2019, the predicted transition for Palestine was March 23rd[1], but
on the 23rd it was reported that it was actually March 30th. The IANA
released a patch on March 25th, 2019[2]. This meant that there were two
days where *current* timestamps in Asia/Hebron and Asia/Gaza were
incorrect as they were operating on an incorrect DST transition. If one
never updated the timezone database, then current timestamps would be
incorrect for all times between the 23rd and the actual DST transition
on the 30th.

[1]: https://mm.icann.org/pipermail/tz/2019-March/027801.html
[2]: https://www.iana.org/time-zones/releases/2019a

-- Peter McGoron